Spray-induced gene silencing using bacterial extracellular vesicles for dsRNA delivery to manage fungal diseases in agricultural and forest systems

Fungal plant diseases are responsible for yield and quality losses in agroecosystems, and also threaten the sustainability of forest ecosystems worldwide. The management of fungal diseases in agroecosystems often relies on the intensive use of chemical fungicides, which have negative impacts on the environment and may lead to the emergence of resistant strains. At the same time, fungal diseases are rarely managed in forest systems due to the scarcity of viable options. Spray-Induced Gene Silencing (SIGS) is a novel management approach based on the ability of certain organisms, including plant pathogenic fungi, to take up double-stranded RNA (dsRNA) from the environment, which can induce gene silencing in the target organism. Thus, essential or virulence-related genes can be specifically targeted by dsRNAs in SIGS, preventing or reducing disease development and providing a bio-based alternative to chemical fungicides in agroecosystems, and a promising option for forest systems. However, the easy degradation of dsRNA under environmental conditions is a major hurdle in adapting this technology for widespread use. Here, we propose to use bacterial extracellular vesicles (BEVs) as dsRNA delivery vehicles in SIGS. My previous research experience has shown that artificial vesicles can encapsulate and protect dsRNAs that target fungal genes through spray applications, inducing gene silencing in several plant pathogenic fungi. In this proposal, we plan to develop a technology based on dsRNA encapsulation into bacterial extracellular vesicles (BEVs) to target two fungal species in the genus Fusarium, one that infects high-value horticultural crops and one that infects forest pine trees. Through a carefully designed plan based on my research background and the expertise of my host institution, we aim to develop SIGS technologies based on BEVs that will contribute to the sustainable management of fungal diseases in agricultural and forest systems.